Atlas 7A Shaper Internal Tool Holder

ErichKeane

Making scrap at ludicrous speed.
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At one point I want to be able to make internal keyways (and don't want to spend money/space on a keyseat meachine), and the shaper seems like the tool to do it! I didn't get a tool holder to do so with, so I figured I'd make one to have in my tools drawer for when I first one one! My goal here was to use a 1/4" square tool to match the existing tool holder. This is what required the ~5/8" shaft. Hopefully if I find myself needing a smaller one I can come up with a better plan. I DO have an idea to mount a small round tool at a 45 degree angle on a much smaller bar, but I chose a more traditional one here.


I have some 1 1/4" bar that I THINK is 4140, it machined pretty cleanly, but I don't remember ever buying a rod this long of anything else. First step was face/center drill.
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I turned down a bunch of it to ~1.180 for the inner 'flange' to the clapper, and the rest down to just under 1" proper to fit in the slot. Here is the test fit.
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I turned down the main shaft to .615, so about 10 under. The goal was to make it small enough I could barely cut a keyway in a 5/8" hole, but still have enough material to hold the 1/4" bit. I also used the parting tool to make a 'gutter' for the threading.

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I single-pointed 1"-20 UNEF threads, though they are a little undersized. See (https://www.hobby-machinist.com/thr...threads-a-comedy-of-errors.84617/#post-749556) for details n how that went :)

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And here it is, fitting just right in the clapper box!

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Next, I took the rest of the 1.180 OD part, and center drilled, then bored it, then started threading it. I used the 45 degree holder section on my boring bar with a ground tool to cut the threads.
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The threads went about 1" deep, and turned out pretty good! I had cut the ID to size, then cut until the blue was basically all gone.

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And, if you read my other thread, I lucked into a nice, tight fit with my bar! I didn't have the ability to test it (and was likely going to remake the bar if need be), but it all fit! I made 2 nuts out of that threaded portion, I think this is the thinner one.

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I considered using a 'pin' wrench on these, but I couldn't find an endmill that would fit my pin wrench. SO, I went with 1-1/16" square, which matches one of the wrenches I have in my lathe caddy.

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I also parted off a small spacer to go where the washer goes. Its a bit thicker than a normal washer (~140 thou?), but it does the trick. Without it, I think I bottom the threads out before getting the bar tight.

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Then, the tool holder part for the bar. I originally tried using a 1/4" endmill with it stood straight up (and had it clamped poorly), and ended up with a crooked, offcenter slot. SO, I turned it on its side and used my 1/8" cutter! This part went easy as pie! I did .252 wide by .245 deep.

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I then flipped it upwards to drill/tap some 4-40 holes.

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Next, I needed to make the 'clamp' to hold the tool in. I found some scrap that came from... something at one point, turned it down to .615, #32 drilled it in 2 places, and #10-32 tapped in the center. You'll see why in a moment!
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And here it is assembled! The side bolts clamp it down more than sufficiently, with a 5 thou undersized slot. I added the #10 bolt for extra assurance, particularly because I wasn't sure I could add it after the fact.

You'll also note in these pictures I put some wrench flats on the side of the bar. These were SUPPOSED to be for a 9/16" wrench, but that fits pretty loosely. Turns out however, my 14mm fits it like a glove, so its now a 14mm. I typically hate mixed wrenches like this, but I didn't feel like putting in the effort for a 1/2" wrench.

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To actually use that, you will need to drill and tap fpr a setscrew to immobilize the clapper box; a drill divot should be drilled in the clapper itself slightly off set from the clapper box itself so that tightening the setscrew tends to seat the clapper against it's seat; my shaper has the setscrews on both sides.
 
To actually use that, you will need to drill and tap fpr a setscrew to immobilize the clapper box; a drill divot should be drilled in the clapper itself slightly off set from the clapper box itself so that tightening the setscrew tends to seat the clapper against it's seat; my shaper has the setscrews on both sides.
Yep, I know about that. I haven't had a chance to do that yet, I was planning on some pretty decent sized set screws next time I go to Ace.
 
Nice job. Some day hopefully not to far in the future I will be able to do that too. Unless I over looked something you plan on cutting the keyway on the forward stroke. My machine does not have the threaded holes on the side to hold the clapper and I am not to keen on drilling and tapping for retaining screws. Hopefully we will hear how well your tool works.
Have a nice day
Ray
 
Nice job. Some day hopefully not to far in the future I will be able to do that too. Unless I over looked something you plan on cutting the keyway on the forward stroke. My machine does not have the threaded holes on the side to hold the clapper and I am not to keen on drilling and tapping for retaining screws. Hopefully we will hear how well your tool works.
Have a nice day
Ray

Apparently it is a problem on the 'push' stroke too, though I have seen some mixed results from others who don't have the screw. Another interesting thing is the manual for the 7B suggests putting a spring SOMEWHERE (I didn't figure it out from the manual) to accomplish the task, but I might just have to do the set-screw anyway. I'd hate myself forever if I broke a tap off in my clapper though :)
 
"To actually use that, you will need to drill and tap fpr a setscrew to immobilize the clapper box; a drill divot should be drilled in the clapper itself slightly off set from the clapper box itself so that tightening the setscrew tends to seat the clapper against it's seat; my shaper has the setscrews on both sides. "

John,
I made a very similar tool holder for my little 7" shaper a few years ago and had not heard of putting the set screws in the clapper. I have only used this tool a couple of times, but it seems to work well. Can you explain the reasoning for locking the clapper with the set screws.
Thanks
Ted
 
My clapper on my 7” Rhodes has that set screw and a divot just as Benmy describes above. Let me know if you want me to take a pic.
 
I have used the same concept a few times. With a cheap (Chinese?) boring bar as the rod. Cutting keyways in a small gear called for a small rod, I think I used a 3/8 with a 1/8 cutter. I had never heard of clamping the clapper so it couldn't lift on return. But with a 3/8 rod in a 1/2 hole, it worked well enough. Those "budget" boring bars have a 90* broach on one end, a 45* on the other. I used the 90* end and ground the tool appropriately.

Having also cut keyways with a broach and with doubled up hacksaw blades (and a file), internal keyways are a matter of how I feel at some particular time. No hard and fast rule.

.
 
I have used the same concept a few times. With a cheap (Chinese?) boring bar as the rod. Cutting keyways in a small gear called for a small rod, I think I used a 3/8 with a 1/8 cutter. I had never heard of clamping the clapper so it couldn't lift on return. But with a 3/8 rod in a 1/2 hole, it worked well enough. Those "budget" boring bars have a 90* broach on one end, a 45* on the other. I used the 90* end and ground the tool appropriately.

Having also cut keyways with a broach and with doubled up hacksaw blades (and a file), internal keyways are a matter of how I feel at some particular time. No hard and fast rule.

.

Those bars are actually where I got the idea for the 45 degree angle. I've only got a 7" shaper, so I won't be able to use the whole boring bar, but I might see if I can find just the small one cheap, cut it in half (probably 1/3rds, throwing out the middle part :) ), and make a holder for it.
 
Looks like I can go down to a 1/4" bar that holds a 5/32" round bit, or 5/16" that holds a 3/16" bit. I think I only have as small as a 3/8" bar.

If I find myself with need for such an internal size (or wanting to just make tooling!), I'd think making one to hold one of those bars cut down. Though, if I'm using round tools, I mind as well just make one with the protrusion and drill the hole.
 
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